The feature will however not be available to all Apple device owners at once. The company said it “is rolling out slowly over the next several weeks” — that’s quicker than the Android deployment, but you’ll still need some patience.

With 800 million monthly active users on the WhatsApp service, this feature has the potential to upset a lot of carriers worldwide who have already seen their SMS revenues decimated by the rise of messaging apps. WhatsApp itself handles more messages from its users than there are global SMS sent each day. It’s worth noting, though, that we don’t know how many are on the iOS app.

Today’s iOS app update also includes a few other nifty features, primarily support for the iOS 8 share extension which allows you to send videos, photos and links to WhatsApp chats from other apps. Users can now also take photos quickly inside chats, and there’s an option to send multiple videos at one time — as you can do with photos — each of which can be cropped and rotated before being shared.

The launch of calling for iOS is the latest in a steady stream of updates aimed at making WhatsApp more useful than a mere free text message replacement. Another advancement was the launch of a desktop web client in January, thereby enabling users to keep in touch even when their smartphone is stowed away.

Yet, WhatsApp doesn’t include additional features, such as business-consumer communication, payments or an app platform, all of which are now part of Facebook’s Messenger service. That doesn’t look like changing for some time, since those differences help Facebook’s messaging apps appeal to a spectrum of audiences — but it does make it difficult for WhatsApp to monetize its service in a meaningful way. For now, at least.